Process for the production of cis-polypentenamers

ABSTRACT

Cyclopentene is polymerized or copolymerized with a catalyst of tungsten hexafluoride and an organoaluminium compound to yield predominantly cis-polypentenamers.

United States Patent Oberkircli et al.

[54] PROCESS FOR THE PRODUCTION OF CIS-POLYPENTENAMERS [72] Inventors: Wolfgang Oberkirch, Cologne; Peter Gunther, Opladen; Gottfried Pampus, Leverkusen, all of Germany [73] Assignee: Farbentabriken Bayer Aktiengesellschaft, Leverkusen, Germany [22] Filed: Oct. 26, 1970 [21] Appl. No.2 83,831

[] Foreign Application Priority Data Nov. 13, 1969 Germany ..P 19 57 025.3

[52] US. Cl. ..260l88.2 R, 260/931 [51] Int. Cl ..C08f 3/02, C08f 7/02, C08f 15/02 [58] Field of Search ..260/93.l, 88.2 R

7a :1: Palypentenamer Aug. 29, 1972 [56] References Cited UNITED STATES PATENTS 3,449,310 6/ 1969 DallAsta et a1. ..260/93.1 3,549,607 12/ 1970 Natta et al. ..260/93.1

Primary ExaminerJoseph L. Schofer Assistant Examiner-Richard A. Gaither Attorney-Connolly and Hutz [57] ABSTRACT Cyclopentene is polymerized or copolymerized with a catalyst of tungsten hexafluoride and an organoaluminium compound to yield predominantly cispolypentenamers.

8 Claims, 1 Drawing Figure /o Trans Palypentenamer PATENTEMuazs m2 mwwwww .GEuc c 0960 M8 8 Al/W INVEIIIORS: GOITTFRYIED murus.

WOLFGANG OBERKIRCH, PETER GUN'IHER,

It is known that cyclopentene can be polymerized with ring opening by using organometallic mixed catalysts of tungsten or molybdenum compounds and organoaluminium compounds to form polypentenamers.

According to German Pat. No. 1,299,868, catalysts containing WCL yield polypentenamers in which most of the double bonds are in the transconfiguration, whilst cis-polypentenamers are formed with molybdenum catalysts.

Previously, it has not been possible to prepare cispolypentenamers in high yields because the molybdenum catalysts suitable for this purpose only have low catalytic activity even when they are used in large quantities. Unfortunately, conventional catalysts based on tungsten halides and organoaluminium compounds whose activity is considerably better than that of the molybdenum catalysts always lead to trans-polypentenamers.

Object of this invention is a process for producing predominantly cis-polypentenamers in which cyclopentene is homo or copolymerized with an organometallic mixed catalyst of tungsten hexafluoride and an organoaluminium compound wherein the molar ratio of aluminum to tungsten is less than 3 to l. The term predominantly cis-polypentenamer means a product having at least 50 percent and preferably at least 70 percent of its double bonds in cis-configuration.

One advantage of the new process is that cispolypentenamers are obtained in high yields with an active tungsten catalyst. By use of the new process cispolypentenamers can be obtained in solution, while conventional molybdenum catalysts used for this purpose are only suitable for bulk polymerization which has considerable disadvantages.

Also using WE, either in the form of gas or in the form of a liquid avoids the difficulties involved both in dosing and in the low solubility of solid WCL r M0Cl The new process is suitable for polymerizing cyclopentene either on its own or together with dicyclic or polycyclic olefins, preferably in quantities of from 0.1 to percent by weight based on cyclopentene. Dicyclopentadiene, norbomene and norbomadiene represent particularly suitable comonomers.

To carry out the process according to the invention, WF is preferably used in a quantity of from 0.05 to mMol and most preferably in a quantity of from 0.2 to 2 mMol per 100 g of monomer.

Suitable organoaluminium compounds include aluminum trialkyls such as (C H Al, (iC I-I Al, aluminum halogen alkyls such as (C I-I AlCl, (C H Al Cl and (C HgAlCl and alkoxy aluminum alkyls such as (C H O)Al(C H Halogen aluminum alkyls are particularly preferred.

To prepare the catalysts, the catalyst components are preferably used in the following molar ratios: aluminum compound: tungsten hexafluoride 0.1:1 to 3:1, preferably 0.1:1 to 2:1.

Cis-polypentenamer is formed at an Al:W ratio of less than 3 and preferably of 2 or less than 2. Transpolypentenamer, (as to be expected from the prior art) is only formed at higher Al:W ratios (greater than 4), as shown by the comparison examples.

The dependence of the polymer configuration upon the particular A1:W ratio is illustrated in FIG. 1.

In FIG. 1, the molar ratio of Al to W in the catalyst is plotted on the abscissa, whilst the cisand trans-bond content of the polypentenamer obtained with a catalyst is plotted on the ordinate. The curves apply to catalysts of the following composition:

Curve 1 (measuring points denoted by x) WF (C H )a z z Curve 2 (measuring points denoted by 0) WE, l-I AlCl Curve 3 (measuring points denoted by A) WE, H )AlCl in the molar ratios indicated by the abscissa.

The process according to the invention is advantageously carried out in solution in inert organic solvents. Suitable solvents include aromatic solvents such as, for example, benzene, toluene, aliphatic and cycloaliphatic solvents such as, for example, hexane, heptane, cyclohexane, and halogenated hydrocarbons such as chloroform and chlorobenzene, for example.

The monomer concentration in the aforementioned solvents preferably is between 10 and 30 percent. The temperature during preparation of the catalyst and during polymerization can be in the range from to +30? C. and is preferably in the range from -50 to 0 C.

WF and the aluminum compound are preferably contacted in the presence of the monomer. Polymerization begins immediately after the organoaluminium compound has been added. The polymerization time can be between 30 minutes and 6 hours.

After the required conversion has been reached, polymerization is stopped, for example by the addition of alcohols, carboxylic acids and/or amines. The polymer solution can have added to it as stabilizer and age-resistor any of the usual products such as, for example, phenyl-B-naphthyl amine, 2,6-di-tert-butyl-4- methylphenol or 2,2'-dihydroxy-3 ,3 -di-tert-butyl-5 ,5 dimethyl-diphenylmethane in quantities of from 0.2 to 3 percent.

The polymers can be isolated in known manner, for example by precipitation with alcohol or by steam distillation.

The polymers obtained in accordance with the invention are valuable rubber-like elastomers which can be processed by known methods.

EXAMPLE 1 trans 0 Calculation. i, trans mma U m (infra-red spectroscopy) trans-double bonds: 23.2 percent EXAMPLES 2 to 4 The Al:W ratio is varied under the conditions of Example 1, in other words varying quantities of ethyl aluminum sesquichloride are used in what is otherwise the same mixture. The influence upon the ratio of cisto trans-double bonds content is shown in Table 1.

" Intrinsic viscosity, measured in toluene at 25C.

COMPARISON EXAMPLES Trans-polypentenamer is obtained under the conditions of Example 1 with an A1:W ratio of 4 in what is otherwise the same mixture. The results are set out in Table 2.

TABLE 2 Comparison Example No. Al/W Yield cis trans [1 A 4 22 l 1.1 88.9 5.7 B 5 31 10.8 89.2 6.0 C 6 32 9.5 90.5 D 7 26 7.1 92.9 E 8 20 7.1 92.9 6.7

intrinsic viscosity, measured in toluene at 25C EXAMPLE 5 COMPARISON EXAMPLE The procedure is as in Example 5 except that the Al/W ratio is 4.0. Yield: 49 percent cis-double bonds: 21.5 percent trans-double bonds: 78.5 percent [17]: 5.6 (intrinsic viscosity, measured in toluene at 25 C.)

EXAMPLE 6 Diethyl aluminum chloride is used as the aluminum component under the conditions of Example 1. The Al/W ratio is 1.5.

Yield: 37 percent cis-doubl bonds: 61.8 percent trans-dou le bonds: 38.2 percent [1;]: 11.7 (intrinsic viscosity, measured in toluene at 25 C.)

We claim:

1. A process for producing predominantly cisoriented polypentenamers which comprises polymerizing cyclopentene in the presence of a catalytic amount of a catalyst comprising tungsten hexafluoride and an organo-aluminum compound in a molar ration of organo-aluminum compound to tungsten hexachloride of from 0.121 to 3:1 at a temperature of from to 30 C.

2. The process of claim 1 wherein said ratio is from 0.1:1 to 2:1.

3. The process of claim 1 wherein said polymerization is carried out in an inert organic solvent.

4. The process of claim 1 wherein from 0.05 to 20 mMol of tungsten hexafluoride is employed per g.

monomer.

5. The process of claim 1 wherein 0.1 to 10 percent by weight of a polycyclic olefin is copolymerized with cyclopentene.

6. The process of claim 1 wherein said organoaluminum compound is aluminum trialkyl, aluminum halogen alkyl or alkoxy aluminum alkyl.

7. The process of claim 1 wherein said organoaluminum compound is aluminum halogen alkyl.

8. The process of claim 1 wherein said temperature is from 5 0 to 0 C. 

2. The process of claim 1 wherein said ratio is from 0.1:1 to 2:
 3. The process of claim 1 wherein said polymerization is carried out in an inert organic solvent.
 4. The process of claim 1 wherein from 0.05 to 20 mMol of tungsten hexafluoride is employed per 100 g. monomer.
 5. The process of claim 1 wherein 0.1 to 10 percent by weight of a polycyclic olefin is copolymerized with cyclopentene.
 6. The process of claim 1 wherein said organoaluminum compound is aluminum trialkyl, aluminum halogen alkyl or alkoxy aluminum alkyl.
 7. The process of claim 1 wherein said organoaluminum compound is aluminum halogen alkyl.
 8. The process of claim 1 wherein said temperature is from -50* to 0* C. 